Stoker fired furnace with reciprocable grate and draft control



June 20, 1950 G. c. MoLoTzAK sToKER FIRED FURNACE WITH RECIPROCABLE GRATE AND DRAFT coN'rRoL.A

2 Sheets-Sheet 1 Filed Nov. 22, 1948 Inventor George C. Mo/ofzak y Amm June 20, 1950 G. c. MoLoTzAK 2,512,236

STOKER FIRED FURNACE WITH RECIPROCABLE *GRATE AND DRAFT CONTROL Filed Nov. 22, 1948 2 Sheets-Sheet 2 III/[lll lll/l lllll//l//l/l/l lll/[1111 lllA Fig. 3.

, Inventor George 6. Mo/olzak WWW Wm...

Patented June 20, 1950 UNITED STATES PATENT OFFICE sToKER- Fiano FURNAGE WITH nacimo- CABLE GRATEAND DRAFT coN'rRoL' George C. Molotzak, lnCoaldale, Ba. ApplicationNovember 22, 19i8, Serial No. k61,406 solaires. (Crim- 38.)

This invention relates to furnaces which are red with solid fuel by means of a mechanical stoker, and which have a grate that is reciprocable to deliver ashes out of .the fuel bed into an ash pit. In furnaces of the above kind, the stoker and grate are usually operated by thermostatically controlled mechanisms so that they are simultaneously thrown into operation when more heat is demanded of the furnace and out of operation when the heat produced by the furnace meets a predetermined demand.

An object of the present invention is to provide a furnace of the abovel kind having an ash pit chamber; an air inlet chamber behind the ash pit chamber, a front rebox over the ash pit chamber, a rear combustion chamber over the air inlet chamber, a transverse bridge wall between the rebox and the combustion chamber, an outlet flue for products of combustion depending within the combustion chamber to a point below the top of the bridge wall, a damper positionable to either close direct communication betweenthe air inlet chamber and the ashpit chamber and simultaneously open direct communica.- tionbetween said air inlet chamber and the combustion chamber or to open direct communication between. the air inlet chamber and the ash pit chamber and simultaneously close direct communication between said air inlet chamber and the combustion chamber. In this way, an updraft of air may be had from the air inlet chainber through the nre bed when more heat is demanded and air may be supplied from the air inlet chamber directly and only to the combustionchamber when the heat produced by the. furnace meets the predetermined demand;

YAnother object is to provide means for positioning the damper to close communication between. the air inlet chamber and the ash pit chamber when the Stoker and grate operating. unit is inoperative and the heat produced by the furnace meets the predetermined demand, and for automatically opening. communication between said air inlet chamber and the ash pit chamber when the stoker and grate operating unit are rendered operative and more heat is demanded. Preferably, the damper is operatively connected to, an centrifugal governor driven by the driving. motor of the operating unit.

vThe exact nature of the present invention, as well as other objects and features thereof, willl becomeapparent from the following description when considered in connection. with.V the accompanying drawings, in which:

Figure 1 is a View partly in vertical section and partly in side elevation;v ofI a lfurnace embodying the present invention; 'i

Figure 2 is a horizontal section taken on the I'ineZ-Z'O'Figure 1;

"Figure 3 is a fragmentary horizontal section taken on the .line 3-3 of Figure 1', with parts omitted;

Figure i is a fragmentary elevational view showing the driving. connection between the motor ofr the operatingv unit and one of the crank discs of the latter.

Referring in. detail to the drawings, I have shown a water heating furnace or boiler B, vthe body of which has water jacketed top, side, front and rear walls, the front wall being provided with a. fuel-feed openingA 5. The interior of the furnace body is divided by a transverse water bridge wall 6i intoa front rebox 'I and a rear combustion chamber 8, and the front wall is connected' tothe bridge wall by rearwardly inclined water tubes 9 and I0, respectively arranged directly above and directly below the fuel feed opening 5; The body of the furnace is mounted on a base I.I which is divided by a transverse partitionv I21into a front ash pit chamber I3 beneath the rebox and a rear air inlet chamber I4be`- neath the combustion chamber. The base II has a top opening I5 providing for communication between the combustion chamber and the air inlet chamber I4, and the partition I2 has an opening I6.- providing for communication between the ash. pit chamber I3 and the air' inlet charnberl I4. The sidewalls of the base have louveredopenings asl at I'I' for the admission of outside air torthe chamber I4. A damper I8 is hinged at ILS" to'swing from thefull line position wherein the same,v closes` the opening yI6 to the .dotted line position wherein it closes the opening I5; and vice versa.

A reciprocable grate 20 is mounted at a rearward inclinationV between the rebox l' and the ash pit. chamber I3, and an operating rod 2l is fixed at one end to the grate and projects outwardly through the front of the furnace. A segmentA gear 22 is fixed to the shaft of damperl and is meshed .by a rack bar 23 carried by the rear end of a second operating rod 24 thatalso projects through the front of the furnace.

A, mechanical; stoker 25 is associated with the furnace to'A feed solid fuelthrough the feed opening onto the grate; Thisv st'oker maybe of thetypey showny in myvU. SPa-tent No.. 2,377,357'dated1 .InnerY 5,l 1945;.4 the. same: embodying "a reciprocate ing feeder plate which is provided with an operating rod 26.

The operating rods 2l, 24 and 26 are operatively connected to a common driving unit or mechanism employing an electric motor 21 and arranged within a casing 28. The grate operating rod 2I is extended into the casing 28 and terminates in a transverse member 29 which has an elongated slot 30 into which projects a lateral crank pin 3l of a combined crank and pulley Wheel` 32 suitably journaled within the casing. The operating rod 26 includes a section 33 attached to the stoker feeder plate, and a section 34 rigidly connected at 35 to the section 33 and projecting rearwardly into the casing 28. The section 34 terminates in a transverse member 36 which has an elongated slot 31 into which projects a lateral crank pin 38 of a second combined pulley and crank wheel 39 which is suitably journaled within the casing above the wheel 32. An endless transmission belt 48 passes around the wheels 32 and 39, and the drive shaft 4I of motor 21 is operatively connected to wheel 39 by a worm gearing 42 as shown in Figure 4.

Associated with the drive shaft 4I of motor 21 is a centrifugal governor 43 which is operatively connected at 44 to the damper operating rod 24. The casing 28 is adapted to be lled with a lubricant, and escape of the lubricant from said casing about the rods 2l and 24 and the rod section 34 is prevented by seals 45 of the bellows type. A thermostatic switch 46, subjectedto the temperature of the water in the water space of the furnace, may control the operation of the motor 21.

Vertical flues 41 project through the top of the furnace and depend within the combustion chamber 8 to a point below the top of the bridge wall 6, said fiues being adapted to carry off the products of combustion and having the portions thereof within the combustion chamber water jacketed as at 48.

When the heat produced by the furnace meets a predetermined demand, the motor 21 is inoperative and the parts are positioned as shown, the main supply of air for promoting combustion being allowed to flow directly from the air inlet chamber I4 into the combustion chamber 8 through opening l and being prevented from owing into the ash pit chamber I3 by damper I8. When more heat is demanded, the motor 21 is thrown into operation so as to actuate the stoker, reciprocate the grate, and swing the damper I8 to the dotted line position. In this way, ashes are shaken from the fire bed into the ash pit chamber, fuel is fed on to the grate by the stoker, and an updraft of air is provided through the fire bed so as to eiectively increase the heat produced by the furnace until it meets a. predetermined demand. The thermostatic switch then throws the motor 21 out of operation so that shaking of the grate and feeding of the fuel is discontinued, and damper I8 is returned to the full line position wherein substantial draft through the re bed is discontinued. Some air may be admitted to the ash pit chamber at all times through a damper 49 provided in the door 58 of the ash pit chamber. Obviously, when the shaft 4I is driven, the Weights of governor 43 move outwardly and cause its springs to flex and thereby move the rod 24 to swing damper I8 to the dotted line position. On the other hand, when shaft 4I discontinues rotation,

4 the rod 24 to return the damper I8 to the full line position.

From the foregoing description, it is believed that the construction, operation and advantages of the present invention will be readily understood and appreciated by those skilled in the art. Modifications and changes in details of construction are contemplated, such as fairly fall within the spirit and scope of the invention as claimed.

Having described the invention, what is claimed as new is:

1. A Water heating furnace having walls and a grate defining a front ash pit chamber, an air inlet chamber directly behind the ash pit chamber, a rebox over the ash pit chamber, and a combustion chamber communicating with and the springs of the governor straighten and move u located behind the iirebox and over the air inlet chamber; one of said walls comprising a transverse bridge wall between the rlrebox and the combustion chamber, another of said Walls being between the air inlet and combustion chambers and having an opening affording communication between said air inlet and combustion chambers when open, still another of said walls being between the ash pit and air inlet chambers and having an opening aording communication between said ash pit and air inlet chambers when open, a ilue for the escape of products of combustion depending within the combustion chamber to a point below the top of the bridge wall, the grate being between the rebox and the ash pit chamber, and a damper mounted in the air inlet chamber and positionable to open either of said openings and simultaneously close the other to selectively establish direct communication between the air inlet chamber and the ash pit chamber or between the air inlet chamber and the combustion chamber.

2. A Water heating furnace having wa1ls and a grate dening a front ash pit chamber, an air inlet chamber directly behind the ash pit chamber, a iirebox over the ash pit chamber, and a combustion chamber communicating with and located behind the firebox and over the air inlet chamber; one of said walls comprising a transverse bridge wall between the fireboX and the combustion chamber, another of said wa1ls being between the air inlet and combustion chambers and having an opening affording communication between said air inlet and combustion chambers when open, still another of said walls being between the ash pit and air inlet chambers and having an opening affording communication between said ash pit and air inlet chambers when open, a ilue for the escape of products of combustion depending within the combustion chamber to a point below the top of the bridge wall, the grate being between the rebox and the ash pit chamber, and a damper mounted in the air inlet chamber and positionable to open either of said openings and simultaneously close the other to selectively establish direct communication between the air inlet chamber and the ash pit chamber or between the air inlet chamber and the combustion chamber, and a motor driven centrifugal governor operatively connected to the damper for positioning the latter so as to close the opening in the wall between the air inlet and ash pit chambers when the driving motor of said governor is rendered inoperative and for positioning the damper so as to close the opening in the wall between the air inlet and combustion chambers when said driving motor is rendered operative.

3. A water heating furnace having walls and a grate defining a front ash pit chamber, an air inlet chamber directly behind the ash pit chamber, a frebox over the ash pit chamber, and a combustion chamber communicating with and located behind the rebox and over the air inlet chamber; one of said walls comprising a transverse bridge wall between the `irebox and the combustion chamber, another of said walls being between the air inlet and combustion charnbers and having an opening affording communication between said air inlet and combustion chambers when open, still another of said Walls being between the ash pit and air inlet chambers and having an opening affording communication between said ash pit and air inlet chambers when open, a flue for the escape of products of combustion depending within the combustion chamber to a point below the top of the bridge wall, the grate being between the firebox and the ash pit chamber, and a damper positionable to open either of said openings and simultaneously close the other to selectively establish direct communication between the air inlet chamber and the ash pit chamber or between the air inlet chamber and the combustion chamber, said grate being reciprocable, a stoker for feeding solid fuel onto the grate, a driving unit including a motor having a drive shaft operatively connected to the grate and the Stoker, and a centrifugal governor operatively associated with said drive shaft and REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,520,922 Baker Dec. 30, 1924 1,778,349 Banfield Oct. 14, 1930 1,831,912 Hoffman Nov. 17, 1931 1,925,803 Hendershott Sept. 5, 1933 2,218,895 Selig, Jr Oct. 22, 1940 

